RE: Cohen's ecologic study reanalyses[Scanned]

[BERNARD L COHEN <blc+@PITT.EDU>]

On Mon, 22 Sep 2003, Dr Christoph Hofmeyr wrote:

> I sincerely believe that you cannot just look at percentage change per pCi/L concentration for the slopes.  If you look at the absolute numbers, there is a difference (ratio) of almost a factor of five between male and female cancer deaths for each average concentration and this ratio is also reflected in the actual (negative) slopes - therefore you get very similar percentages for the slopes (males and females).  Since one must assume very similar exposures for males and females, such a large difference in lung response is highly improbable.  Additive effects are effectively ruled out.  What weird kind of multiplicative effect would one have to postulate for radon (modification of inherent or induced lung cancer propensity) to describe both curves.  A possible (some would say probable) explanation is that radon cannot be a significant factor.  A perplexing problem.



	--The BEIR-IV theory is that lung cancer is basically a disease of

smokers and radon affects the risk equally for males and females. It is

well known that the difference in lung cancer rates between males and

females is due to differences in smoking prevalences, which have been

changing rapidly with time.

	I see no objections to the above aspect of the BEIR-IV theory.

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